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Animals: From Cells to System
s
AgendaAnticipation guideCell differentiation/specializationAbnormal DevelopmentChernobyl (video) Break (5 min)Types of tissuesIn class work
Anticipation GuideA or D
Question A or D
All cells in the body of an animal are specializedThe environment has little to no impact on cell specialization.It is possible for an animal to be born a Cyclops.Like some plants, animals have four main tissues.Cells that are near one another may impact cell specialization
3.1 Cells and TissuesThe adult human body is
estimated to have between 75 to 100 trillion cells!
Some of these cells are non-specialized while most of the cells are specialized (i.e. differentiated)
Cell Differentiation/SpecializationThere are 3 main factors that
influence cell specialization 1. The contents of the cell’s
cytoplasm2. Environmental conditions3. The influence of neighbouring cells
Let’s look at each of these factors individually
Factor 1: Influence of the Cytoplasm on Cell Specialization In mitosis each daughter cell receives
identical sets of chromosomes.However, each cell will contain a different
cytoplasmic content (i.e. larger vacuole, more ribosomes, etc)◦ This results in the production of different
signals for cell specialization.
Factor 2: Environmental Influence on Cell Specialization
Some environmental factors that can impact cell specialization are: ◦Temperature
E.g. Siamese Cats dark feet, tails, ears and nose due to cold temperatures
◦Presence or lack of nutrients◦ Toxins
Factor 3: The Effect of Neighbouring Cells on Cell Specialization
Neighbouring cells tend to have the largest impact on cell specialization.◦They send signals to nearbycells which alters their DNA.
◦E.g. Digit (finger) formationduring development.
The Effect of Neighbouring Cells on Cell Specialization
E.g. 2: 12 Day Old Chick Embryo
Abnormal DevelopmentThe environment plays a critical role in
normal development of the embryo. If exposed to toxins, contaminants,
radiation, or other harmful chemicals the embryo may develop abnormalities.
Cyclops lamb: Veratrum Californicum (contains cyclopamine)
Human Abnormal Development
Approximately 6% of worldwide babies born each year are born with
an abnormality!
◦With increasing abnormalities, it will be “normal” to have an abnormality.
Fetal Alcohol Syndrome
Cleft Palate
Anencephaly
Chernobyl (Radiation Abnormalities)
Break Time (5 min)
From Cells to TissuesWhen a group of cells come together to
carry out a specific function they form a
TISSUE
Animals have four main tissues:◦ Epithelial◦ Muscle◦ Nervous◦ Connective
Epithelial TissueLines the inner and outer surfaces
of the human body (including organs)◦Functions of epithelial cells include
secretion, absorption, protection and transcellular transport.
Can be subdivided into skin epithelia and columnar epithelia
Types of Epithelial Tissue ◦Skin Epithelia: Creates a
barrier between the inside and the outside of the body Mainly for protection
◦Columnar Epithelia: Found in the small intestine, stomach and glands. It functions to absorb nutrients and secrete mucus.
Muscle TissueConsists of elastic-like cells that
contract.Can be subdivided into skeletal
muscle, smooth muscle, and cardiac muscle.
Types of Muscle TissueSkeletal Muscle: Connects to the bone
allowing movement. ◦Voluntary
Smooth Muscle: Found along the walls of blood vessels and internal organs (i.e. oesophagus and stomach)◦ Involuntary
Cardiac Muscle: Found only in the heart
Nervous TissueMade of cells called neurons.
Function to receive and conduct electrical signals.◦Relay signals to the central nervous
system (brain and spinal cord).◦Detects and responds to external
stimuli.
Connective TissueTissue that functions to
strengthen, support, protect, bind, or connect cells and other tissues.◦ Can be subdivided into Bone Tissue,
Fat (adipose tissue), and Blood Tissue.
Types of Connective TissueBone: Made of many cells
enveloped in calcium.
Fat: A collection of large, tightly packed cells found under the skin and around organs.
Blood: A collection of red and white blood cells, platelets, and plasma.
Anticipation Guide RevisitedA or D
Question A or D
All cells in the body of an animal are specializedThe environment has little to no impact on cell specialization.It is possible for an animal to be born a Cyclops.Like some plants, animals have four main tissues.Cells that are near one another may impact cell specialization
Test Your KnowledgeWhich tissue prevents harmful bacteria from
entering your body?Which tissues are responsible for supporting
and forming bone?Imagine you are opening a water tap in your
washroom. Immediately after touching the water, you realized the water was boiling. Which tissues are involved in moving your hand away quickly?
Which tissue is responsible for controlling the contraction of blood vessels?
Homework/ In Class WorkRead pages 85-92.Practice Questions 1,3, 4 (page
90)
DAY 2
AgendaStory TimeStem CellsPluripotency vs TotipotencyUse of Embryonic Stem CellsControversy of Stem CellsPros and Cons of Embryonic Stem Cells (T-
Chart)Different types of Stem Cells In-class work/Assignment
Story Time
Stem CellsAnalogous to the meristematic
cells in plantsAre unspecialized non-
differentiated cells
Totipotent Stem CellToti- : Means Total-potent : Means PotentialBy combining the prefix and
suffix we can make sense of the meaning of the word.
Totipotent cells are therefore cells that have the potential of forming all total cells possible
Pluripotent Stem CellsPluri- : Means plural or multi-potent : Means PotentialBy combining the prefix and
suffix we can makes sense of the meaning of the word.
Pluripotent cells are therefore cells that can make many different types of cells (but not all).
Pluripotent vs Totipotent
Fertilized egg
Early EmbryoEmbryo (Day 5)
Blastocyst
Trophoblast
Embryonic Stem (ES) CellsFound in early embryo’s (<1
week old)Are pluripotentAre used by scientists to treat
various illnesses and conditions
E.g. 1 Use of ES Cells Cardiovascular diseaseLack of oxygen kills
heart cellsHeart cells cannot
replenish themselvesES cells can be
inserted into the heart to regenerate new heart cells
E.g. 2 Type 1 Diabetes Cells in the pancreas that
produce insulin (controls blood sugar) are attacked by the own body’s immune system◦ES Cells help replenish insulin
producing cells
Controversy Attaining a sample of ES cells
involves destroying an embryo.◦These embryo’s are usually in vitro
(fertilized in a test tube)
Is it ethically right to kill an embryo for the sake
of medical advancement?
T-Chart: Pros & Cons
Additional Types of Stem Cells
Adult Stem Cells• Are tissue specific stem cells.
(i.e. Neural stem cells can produce all types of nerve cells• Commonly used to restore bone
marrow cells in patients that have received chemotherapy.
Fetal Stem CellsTaken from fetus (10 weeks
old) Are tissue-specific
Cord Blood Stem Cells Taken from umbilical cord at
birthUsed to treat the blood system
after cancer treatments (i.e. chemo)
Additional Types of Stem Cells
Induced Pluripotent Stem Cells (iPS)
Reprogramming of specialized cells (i.e. skin cells) into an embryonic stem cells. ◦Are pluripotent◦Behave slightly different that ES cells.
Additional Types of Stem Cells
Assigned WorkReread section 3.1Answer questions #4-8Assignment
◦Create a newspaper article documenting one use (treatment) for embryonic stem cells.
◦The article should include the 5W’s and the How component.
◦Due Monday
E.g. Burn Victims and Stem Cells
Burned tissue takes up to 30 days to begin healing in patients with 2nd degree burns
By placing ES cells at the region that is burned using a spray on method, the recovery can be reduced by over 3 weeks.